Background: The role of eosinophils in thrombotic processes is well known, and the prognostic value of eosinophil to monocyte ratio had been determined in patients with ST elevated myocardial infarction and acute ischemic stroke in recent studies. We aimed to evaluate the impact of the eosinophil-to-monocyte ratio on short- and long-term allcause mortality in patients with pulmonary embolism, which is another clinical condition closely related to the thrombotic pathway.

Methods: In this study, a total of 212 retrospectively evaluated patients with intermediate-high risk and high-risk pulmonary embolism who underwent catheter-directed therapies with ultrasound-assisted thrombolysis or rheolytic thrombectomy (Angiojet©) and intravenous thrombolytic treatment were included.

Results: The median Pulmonary Embolism Severity Index score was 105 (86-128; interquartile range: 25-75, min-max: 35-250). The intermediate-high status and high-risk status were noted in 83.5% and 16.5% of the patients, respectively. All of the reperfusion strategies resulted in significant improvements in the measures of pulmonary arterial pressure and right ventricular strain. Death was recorded in 42 (18.6%) patients during the follow-up period (median 1029 days, interquartile range: 651-1358). Multiple Cox regression analysis revealed that a higher pulmonary embolism severity index score (from 85 to 128; hazard ratio=3.00; 95% CI: 2.11-4.29; P <.001) and a lower eosinophil-to-monocyte ratio (from 0.02 to 0.24; hazard ratio=0.56; 95% CI: 0.34-0.98; P =.032) were 2 independent predictors for long-term all cause mortality. The eosinophil-to-monocyte ratio at the admission of less than 0.03 was documented to be associated with higher mortality (P <.001).

Conclusion: Our results revealed that a lower eosinophil-to-monocyte ratio and a higher pulmonary embolism severity index score independently predict the long-term mortality in patients with intermediate-high- and high-risk pulmonary embolism.